Pipe Length

Overview

Engineering reference data for Pipe Length in fluid mechanics.

Key Formulas

Reynolds Number

$Re = \frac{\rho v D}{\mu}$

Ratio of inertial to viscous forces — determines flow regime.

Bernoulli's Equation

$P + \frac{1}{2}\rho v^2 + \rho g h = \text{const}$

Conservation of energy for steady, inviscid, incompressible flow.

Continuity Equation

$A_1 v_1 = A_2 v_2$

Conservation of mass for incompressible flow.

Darcy-Weisbach

$\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}$

Pressure drop due to friction in a pipe.

Variables

Symbol	Description	Unit
$Re$	Reynolds number	—
$\rho$	Fluid density	kg/m³
$v$	Flow velocity	m/s
$D$	Characteristic dimension	m
$\mu$	Dynamic viscosity	Pa·s
$P$	Pressure	Pa
$f$	Darcy friction factor	—

Standard Pipe Length Types

Pipe lengths are specified in industry-standard categories:

• Single Random Length: Typically 18 - 25 feet for plain-end pipes, or 18 - 22 feet for threaded and coupled pipes.
• Double Random Lengths: Pipes manufactured to lengths between 38 - 40 feet.
• Longer than Double Random: Pipes with lengths exceeding 38 - 40 feet.
• Cut Lengths: Pipes cut to fixed lengths with a tolerance of ±1/8 inch. Some cut lengths are available up to approximately 80 feet.

Unit Conversion

The conversion factor between feet and meters is given by:

$1 \, \text{ft} = 0.3048 \, \text{m}$

This formula is essential for converting pipe length measurements from imperial to metric units.

References

• Original Source